"It heals faster," "its collagen turns over rapidly," and "it is not affected by diabetes;" these are but some of the myths concerning the biological behavior of gingival tissue. By quantitating the catabolism of recently synthesized and fibrillar collagen in incisor gingiva of control rats, a profile of its catabolism can be compared to that of skin or other connective tissues. Furthermore, the effect of diabetes (streptozotocin-induced and spontaneously developed in "BB" rat) as well as inflammation (antigen-antibody-induced) can be accurately assessed using this "profile" approach. In parallel to the profile studies, insight into the mechanism for catabolizing both pools of collagen will be achieved by quantitating their degradation products. The mechanisms examined by the "degradation-products" approach will be: 1) intracellular degradation of procollagen; 2) extracellular degradation of recently synthesized collagen; and 3) extracellular degradation of fibrillar collagen. Together, the "profile" and "degradation-products" approaches should provide an accurate assessment of collagen's catabolism with which to support or dispel some of the myths surrounding the properties of gingival collagen.